зеркало из https://github.com/github/ruby.git
* bignum.c (bigmul1_karatsuba): remove temporal bignum.
* bignum.c (bigsqr): call bigmul0(x, x) because it is faster than the original bigsqr at this point. * bignum.c (rb_big_pow): a value returned from bigsqr is already truncated. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@20739 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
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mame
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10
ChangeLog
10
ChangeLog
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@ -1,3 +1,13 @@
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Sun Dec 14 22:31:19 2008 Yusuke Endoh <mame@tsg.ne.jp>
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* bignum.c (bigmul1_karatsuba): remove temporal bignum.
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* bignum.c (bigsqr): call bigmul0(x, x) because it is faster than the
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original bigsqr at this point.
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* bignum.c (rb_big_pow): a value returned from bigsqr is already
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truncated.
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Sun Dec 14 21:13:02 2008 Yusuke Endoh <mame@tsg.ne.jp>
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* bignum.c (bigmul1_karatsuba): fix comment and refactoring.
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82
bignum.c
82
bignum.c
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@ -1632,12 +1632,14 @@ big_split(VALUE v, long n, VALUE *ph, VALUE *pl)
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hn = RBIGNUM_LEN(v) - ln;
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while (--hn && !BDIGITS(v)[hn + ln]);
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h = bignew(++hn, 1);
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h = bignew(hn += 2, 1);
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MEMCPY(BDIGITS(h), BDIGITS(v) + ln, BDIGIT, hn);
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BDIGITS(h)[hn - 1] = 0;
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while (--ln && !BDIGITS(v)[ln]);
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l = bignew(++ln, 1);
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l = bignew(ln += 2, 1);
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MEMCPY(BDIGITS(l), BDIGITS(v), BDIGIT, ln);
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BDIGITS(l)[ln - 1] = 0;
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*pl = l;
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*ph = h;
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@ -1648,7 +1650,7 @@ static VALUE
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bigmul1_karatsuba(VALUE x, VALUE y)
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{
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long i, n, xn, yn, t1n, t2n;
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VALUE xh, xl, yh, yl, z, t1, t2, t3;
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VALUE xh, xl, yh, yl, z, t1, t2;
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BDIGIT *zds;
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xn = RBIGNUM_LEN(x);
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@ -1707,17 +1709,30 @@ bigmul1_karatsuba(VALUE x, VALUE y)
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i = xn + yn - n;
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bigsub_core(zds + n, i, BDIGITS(t1), t1n, zds + n, i);
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/* t1 <- xh + xl */
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t1 = bigadd(xh, xl, 1);
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/* xh <- xh + xl */
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if (RBIGNUM_LEN(xl) > RBIGNUM_LEN(xh)) {
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t1 = xl; xl = xh; xh = t1;
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}
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bigadd_core(BDIGITS(xh), RBIGNUM_LEN(xh),
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BDIGITS(xl), RBIGNUM_LEN(xl),
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BDIGITS(xh), RBIGNUM_LEN(xh));
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/* t2 <- yh + yl */
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t2 = (x == y) ? t1 : bigadd(yh, yl, 1);
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/* yh <- yh + yl */
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if (x != y) {
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if (RBIGNUM_LEN(yl) > RBIGNUM_LEN(yh)) {
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t1 = yl; yl = yh; yh = t1;
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}
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bigadd_core(BDIGITS(yh), RBIGNUM_LEN(yh),
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BDIGITS(yl), RBIGNUM_LEN(yl),
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BDIGITS(yh), RBIGNUM_LEN(yh));
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}
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else yh = xh;
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/* t3 <- t1 * t2 */
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t3 = bigmul0(t1, t2);
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/* t1 <- xh * yh */
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t1 = bigmul0(xh, yh);
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/* add t3 to middle bytes of the result (z1) */
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bigadd_core(zds + n, i, BDIGITS(t3), big_real_len(t3), zds + n, i);
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/* add t1 to middle bytes of the result (z1) */
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bigadd_core(zds + n, i, BDIGITS(t1), big_real_len(t1), zds + n, i);
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return z;
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}
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@ -2281,48 +2296,7 @@ rb_big_fdiv(VALUE x, VALUE y)
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static VALUE
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bigsqr(VALUE x)
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{
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long len = RBIGNUM_LEN(x), k = len / 2, i;
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VALUE a, b, a2, z;
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BDIGIT_DBL num;
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if (len < 4000 / BITSPERDIG) {
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return bigtrunc(bigmul0(x, x));
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}
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a = bignew(len - k, 1);
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MEMCPY(BDIGITS(a), BDIGITS(x) + k, BDIGIT, len - k);
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b = bignew(k, 1);
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MEMCPY(BDIGITS(b), BDIGITS(x), BDIGIT, k);
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a2 = bigtrunc(bigsqr(a));
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z = bigsqr(b);
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rb_big_realloc(z, (len = 2 * k + RBIGNUM_LEN(a2)) + 1);
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while (RBIGNUM_LEN(z) < 2 * k) {
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BDIGITS(z)[RBIGNUM_LEN(z)] = 0;
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RBIGNUM_SET_LEN(z, RBIGNUM_LEN(z)+1);
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}
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MEMCPY(BDIGITS(z) + 2 * k, BDIGITS(a2), BDIGIT, RBIGNUM_LEN(a2));
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RBIGNUM_SET_LEN(z, len);
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a2 = bigtrunc(bigmul0(a, b));
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len = RBIGNUM_LEN(a2);
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for (i = 0, num = 0; i < len; i++) {
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num += (BDIGIT_DBL)BDIGITS(z)[i + k] + ((BDIGIT_DBL)BDIGITS(a2)[i] << 1);
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BDIGITS(z)[i + k] = BIGLO(num);
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num = BIGDN(num);
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}
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if (num) {
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len = RBIGNUM_LEN(z);
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for (i += k; i < len && num; ++i) {
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num += (BDIGIT_DBL)BDIGITS(z)[i];
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BDIGITS(z)[i] = BIGLO(num);
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num = BIGDN(num);
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}
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if (num) {
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BDIGITS(z)[RBIGNUM_LEN(z)] = BIGLO(num);
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RBIGNUM_SET_LEN(z, RBIGNUM_LEN(z)+1);
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}
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}
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return bigtrunc(z);
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return bigtrunc(bigmul0(x, x));
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}
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/*
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@ -2372,7 +2346,7 @@ rb_big_pow(VALUE x, VALUE y)
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break;
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}
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for (mask = FIXNUM_MAX + 1; mask; mask >>= 1) {
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if (z) z = bigtrunc(bigsqr(z));
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if (z) z = bigsqr(z);
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if (yy & mask) {
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z = z ? bigtrunc(bigmul0(z, x)) : x;
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}
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